<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title></title>
    <meta name="description" content="">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="">
    <style>
      .aaa{
        & .span_1{
          color: red;
        }
        & span{
          &:not(.span_2){
            background-color: #ccc;
          }
        }
      }

      .span_1 {
        color: blue;
        @nest .bbb &{
          color: red;
        }
      }
    </style>
  </head>
  <body>
    <script src="" async defer></script>
    <div class="aaa">
      <h4>aaa---------</h4>
      <span class="span_1">1111</span>
      <span class="span_1">1111</span>
      <span class="span_1 span_2">1111</span>
    </div>

    <div class="bbb">
      <h4>bbb----------@nest</h4>
      <span class="span_1">1111</span>
      <!-- <span class="span_2">1111</span> -->
    </div>
  </body>
</html>